Matt has decided to purchase his textbooks for the semester. His options are to purchase the books online with next day delivery at a cost of $175, or to drive to campus tomorrow to buy the books at the university bookstore at a cost of $170. Last week he drove to campus to buy a concert ticket because they offered 25 percent off the regular price of $16.The benefit to Matt of driving to campus to buy the concert ticket last week was:

A. $9
B. $16
C. $2
D. $4

Answer: D